Maybe SRT, but it doesn't have much platform support itself, and its spec is pretty strange. I get weird Adobe flashbacks about it, since it seems so heavily pushed by Haivision, and it's really made for a different use case - it's made for big broadcasters like ESPN and TV networks, not for web startups.
The current motion seems to be towards hacking WebRTC to accommodate broadcast ingest. But WebRTC is really huge and complicated and you only want a tiny sliver of it for this use case. Pretty much all implementations are buggy because its such a gigantic kitchen-sink design.
There's also RIST (for those who love working groups) and Zixi (for those who love closed source protocols?).
I honestly think that something like HLS could do pretty well (broadcaster slices video into 1-second TS segments and just ships em with HTTP POST), but it's not something I ever saw anyone do. Definitely doesn't meet the TV networks' needs, but its really easy to scale and straightforward to secure, which is maybe more important.